Method for propelling rockets and rocket fuels



METHOD FOR PROPELLING ROCKETS AND ROCKET FUELS John E. Mahan, Bartlesville, kla., assignor to Phillips Petroleum Company, a corporation of Delaware No Drawing. Application July 6, 1953 Serial No. 366,381

39 Claims. (Cl. 6035.4)

This invention relates to rocket fuels. In one of its more specific aspects, this invention relates to hypergolic fuels. In another of its more specific aspects, this invention relates to a method for propelling rockets.

This application is a continuation-in-part of my US. application, Serial No. 257,973, filed November 23, 1951, now abandoned.

My invention is concerned with new and novel rocket propellants and their utilization. A rocket or jet propulsion device, such as is discussed herein is defined as a rigid container for matter and energy, so arranged that a portion of the matter can absorb the energy in kinetic form and subsequently eject it in a specified direction. The type rocket to which my invention is particularly applied is that type rocket propulsion device designated as a pure rocket, i.e., a thrust producer which does not make use of its surrounding atmosphere. A rocket of the type with which my invention is concerned is propelled in response to the steps of introducing a propellant material into a combustion chamber therein, and burning it under conditions that will cause it to release energy at a high but controllable rate immediately after its entry into the combustion chamber.

Rocket propellants in liquid form are advantageously utilized inasmuch as the liquid propellant materials can be carried in a light weight, low pressure vessel and thereafter be pumped into the combustion chamber. It is thus necessary that the combustion chamber, although being strong enough to stand high pressure and temperature, .need be only large enough to insure combustion. The flow of liquid propellants into the combustion chamber can be regulated at will so that the thrust resulting from continuous or intermittent bursts of power can be sustained. Intermittent burning of the fuel contributes to a longer life of the combustion chamber and of the thrust nozzle.

Various methods and liquid combinations have been found'to be useful as rocket propellants. Some propellants consist of a single material, and are termed monopropellants. Those propellants involving two materials are termed bipropellants and normally consist of an oxidizer and a fuel. Hydrogen peroxide and nitromethane are each well known monopropellants. ,Well known bipropellants include hydrogen peroxide or liquid oxygen as the oxidant with a fuel component such as ethyl alcohol-water, ammonia, hydrazine or hydrogen. Additional known bipropellants include nitric acid as the oxidizer with aniline or furfuryl alcohol as the hypergolic fuel component.

When employing 90-l00 percent nitric 'acid, i.e., white fuming nitric acid as the oxidizer in a rocket bipropellant fuel, it is often necessary, dependent upon the specific fuel component, to obtain more efiective ,atent the oxidizer. For this reason such a bipropellant material is referred to herein as being hypergolic. A ratio of oxidizer to hypergolic fuel, based upon stoichiometric amounts, can be utilized within the limits of 0.5:1 to 15:1 if desired. The efiiciency of combustion is less at a ratio below 1:1 and the use of the oxidizer is less economical at ratios above 1:1. However, practical consideration may necessitate the use of'higherratios, even as high as 6:1.

Each of the following objects of the invention will be obtained by the various aspects of this invention.

An object of this invention is to provide new rocket propellants. Another object of the invention is to. provide a novel hypergolic fuel. Another object of the invention is to provide a method for producing immediate thrust to a rocket-type device. Another object is to provide an improved fast-burning fuel. Other and further objects will be apparent to those skilled inthe art upon study of the accompanying disclosure.

In accordance with the broad aspects of this invention, I have found that organic polyamines, either in the presence or absence of normally liquid hydrocarbons form a fuel component which is highly hypergolic and-suit-, able for use in the propulsion of rockets, guided missiles, and the like, in conjunction with an oxidizer. I have further found that these organic polyamines together with selected mercaptans, both more fully set forth hereinbelow, either in the presence or absence of normally liquid hydrocarbons, form a fuel component which is also highly hypergolic and suitable for the uses set forth above. The fuels of the present invention are composed of (l) at least one organic polyamine or mixture thereof, or (2) at least one organic polyamine or mixture thereof with at least one selectedv mercaptan, either of the latter components being suitable in a major or minor amount. When a selected. mercaptan is used as one of the fuel constituents, it is preferred that the mixtures contain at least 10 percent of the organic polyamines and not more than 90 percent of the organic polyamines. In some instances, lesser amounts of the organic polyamine substituents can be ignition than would normally be obtained, by dissolving from 6 to 23 percent by weight of nitrogen dioxide in white fuming nitric acid, thereby forming red fuming nitric acid. A fuel component ofthe bipropellant type described herein is spontaneously ignited upon contacting used.

More specifically and in accordance with my invention, those organic polyamines are used or more substituent R-N groups attached to one or more carbon atoms wherein one or both Rs is selected from the group consisting of a hydrogen atom and a hydrocarbon radical and wherein the total number of carbon atoms present in said polyamine is not greater than 30. Suitable hydrocarbon radicals (those radicals which contain only hydrogen and carbon atoms) are the alkyl, alkenyl, cycloalkyl,

cycloalkenyl, aryl, alkaryl, and aralkyl radicals. carbon atom to which the substituent The group is attached may be a cyclic (carbocyclic) carbon include the various alkane polyamines such as 1,3-butanediamine; 1,5-diaminopentane; 1,4-diaminopentane; 3-(n-' propylamine) propylamine; l-(dimethylamino)-4-aminopentane; 1,3-propanediamine; 2,5-octanediamine; 1,5-di;

aminoheptane; 1,5 -diaminooctane; 1,3,5 -triaminooctane;

1,9-nonanediamine; 1,3,5,8-octanetetramine; 2-amino-3- Patented Jan. 5, 1960 which contain two;

diamine;

(ntorloeth'yla'mino) butane; guanidine; 1,2-propanediatetraethylpropene-1,3 diamine; -N,N,N' ,Nf-tetra(-Z-meth ylallyl)propene-'l,B-diarnine; N,N,N,N'.- tetrocrot'ylpropene-l,3-diamine; N, N"-diallyl N,N' di(3-buteriyl)propene-1,3-diamine; -N,N,N,NPtetraallyI-Z-methyIpropene- 1,3-diamine; N,N diall-yl-N,N'-dimethylpropene-l,3-diamine; N,N'-dicrotyl-N,N'-dipropylpropene-l,3-diamine;

N,N,N',N' tetramethyl 2-methylpropene-1,3-diarnine;

and the like; various aryl (aromatic) diamines and aryl polyamines such as ortho-, metaor para-diaminobenzene; l-'methyl-2,3-diaminobenzene; 1,3,5-triain'inobenzene; various alkaryl .polyamines such as l n-butyl- 3,5-diamin'obenzene; "l-hexyl 2,3,4-triaminobenzene; 1- ethyl-3-diethylamino-S-aininobenzene; and various aralkyl polyamines such as 1-amino-3-(2-aminopropyl) benzene;. 1,3 diamino 5 [2(2 -aminoethyl)-3-azapentane]- benzene; and 1,3-diamino-5[2(2-aminoethyl)-3-ethyl 3- a'zapentanel-benzene.

In addition to the above recited specific compounds, the total reaction mixture or fractions thereof from the preparation of N,N,N ,N-tetraallyl-, tetramthylallyb,

or tetracrotylpropene-l,3-diamine, is useful as a con-' stituent of'hyp'ergolic fuel compositions according to the present invention. These compounds are known in the art -and can be prepared by the manner described in US. Patent 2,565,529 by C. W. Smith, wherein a suitable alpha, beta-unsaturated aldehyde is reacted with one more secondary monoamines having attached to the nitrogenatom at least one alkenyl group with an olefini'c bond in the '2,3-position relative to the hydrogen atom or by other similar methods. V

.Cycloalkyl polyamines and cycloalltenyl polyamines such as 1,3,S-triaminocyclohexane; -1,2- diaminocyclo-' pentane; 3,4-diaminocyclopentene; and 'l,2-diaminocyclobutane are also useful. I

As indicated hereinbefgrje and in accordance with my invention, the amino groups of the above-described polyamines may besubstituted amino groups containing the above-named hydrocarbon groups orothersubstituent groups containing only carbon, hydrogen and nitrogen atoms. r Y

The fuel constituents of the present invention, .i.e.,-

organic polyamines, are hypergolic in an undiluted state and are. also hypergolic when admixed with non-hypergblic materials, particularly hydrocarbons, in a state of dilution as high as 70 percent'by volume of diluent when white fuming nitric acid is used as the oxidant. able non-hypergolic materials which also may form a portion of'the fuel composition include paraffin, cycloparfiin, and aromatic hydrocarbons in the C to C 6 range or mixture thereof, preferably'the normallyliquid materials. Examples of such hydrocarbon fuels are'normal pentan e, normal hexane, normal heptane, benzene, -keros ene, isooctane, diisopropyl, diisobutylene,cyclohexene, cyclohexane, isodec'ane, methylcycl'ohexane, toluene, hexadecane, eicosane, hexacosane, pentatricontane, pi cene, cyclononacos'ane, methylaltetraphenylethylene and the'like. Hydrocarbons in the C to C =rang'e' are preferred.

golic fuels in addition to white or red fuming nitric acid and can be used in the bipropellant fuel compositions of our invention. Suitableoxidants include materials such as hydrogen peroxide, ozone, nitrogen tetroxide,

liquid oxygen and mixed acids, especially anhydrous mixtures of nitric and sulfuric acids such as to 90.

percent by volume of white or red fuming nitric acid audio to 20 percent b y volume anhydrous or fuming sulfuric acid. It is within the scope of this invention toemploy, preferably dissolved 'in the oxidizer, ignition catalysts or oxidation catalysts. 'These oxidation catalysts include certain metal salts, such as the chlorides and naphthenates of iron, zinc, cobalt and similar heavy materials. As an added feature of this invention the organic polyamines are also useful for "providing fast burning fuels for use in rocket engines and the like wherein a hypergolic fuel is not necessarily required. For example, the'fu'el components of this invention are dispersed in a hydrocarbon, suchas the hydrocarbon diluents described above. 'Even if theresulting solution is not hypergolic with an oxidant such as fuming nitric acid, it can be used togethenwith an oxidant and al1ltable igniter as a rocket'propellant. These fast burning fuels are particularly useful if, for various reasons, a hypergolic fuel is not desired or required. The organic polyamines of this inventionmay be added'to ahyd'roa carbon'fucl in a minor amount, usually from 1 'to' 20 percent by'volume of the total mixture to p'roduce fastburning fuels which are 'non-hypergolic. Suitable fast burning fuels comprise from 1 to 20 percent by volume of an organicpolyamide described above with to 99 percent by volume of a petroleum fraction gasoline boiling range. Specifically, such a fuel can comprise between 1 and 20 percent by volume of a propenediamine' and 80-to 99 percent by'volume normal heptane.

As pointed out above, selected 'rnercaptans m'ayfibe used to form a portion of the'hypergolic fuel constituents of this invention in admixture with the above "described organic polyamines. The mercaptans which are suitable for use as such a hypergolic fuel constituent include compounds of the general formula RSH, whereinR is selected from the group consisting of alkyl and alkenyl groups containing from 3 to 10 carbon atoms. Illustrative of "the mercap'tans used in this invention are tertbutyl mercapt'an, isopropyl mercaptan, allyl-mercapt'an, n-butyl mercaptan, 'nehexyl "mercaptan, tert-hexyl mercaptan, tert octyl-mercaptan, nonyl mercaptan, tert=decyl' merca'ptan, and the like. I

Afuel ofthe present invention, 'i.e'., mixtures consisting'of atleast'bneforganic polyamine and at Ieas'tone mercaptan are hypergolic 'i'n anundiluted state. and are also hypergolic when admixed with non-hypergolic mat'erials, particularly those normally liquid 1 hydrocarbons set forth above, when'u'singsuc'h hydrocarbons in amounts as highlas 50 percentby volurne of hydrocarbon whe'n white fuming nitric acid is-us'ed as the oxidant. The invention is 'illustrate'd in-the following examples. Thereacta'nts'and their'proportions and the specific ingredients are presented as being typical and -not'to"-be construed as unduly limiting the invention.

Example I V jThe'frnateria'ls described below 'were tested for spontaneous ignition employing fuming nitric acids as the oxidizer. Ineach test'one part by volumeof a hydrocarbon .polyamine'solution was dropped into a vessel containing-23 parts by volume-furning-nitric acid. The

, candidate polyarnin'e was dissolvedin n-h'eptane or ben- I zene sjo as, to determine the maximum hydrocarbondilw ti'on possible while "still retaining the propertybf hy-Wrgolicity. 'Those rnixtures below the maximum percentage were all hyper g'olic, ineludingthe undiluted polya'mine itself. Tests were conducted at room temperature, about 70 F. The results are set forth below.

Example II Tests similar to those set forth in Example I were also conducted at 40 F. The results are set forth below.

Maximum Dilution, Polyamine Oxidant Percent Volume n-heptane 1,3-butauediamiue Red Fuming Nitric Acid 50 Do White Fuming Nitric Acid 50 Example III A reaction flask fitted with thermometer, dropping funnel, reflux condenser and stirring unit was charged with a mixture of 50 grams of finely powdered anhydrous potassium carbonate, 150 grams of diethyl ether and 194 grams of diallylamine. As the mixture was stirred vigorously, 56 grams of acrolein were slowly added with cooling to maintain the reaction mixture between 10 and 15 c. 50 to 59 F.). After all the acrolein had been added, the reaction mixture was kept at 5 to 10 C. (41 to 50 F.) and stirred for 17 hours. The contents of the reactor were then filtered to remove the solid desiccant; a dark-red filtrate was recovered. The ether and low boiling components, including unreacted acrolein and diallylamine, were removed by fractional distillation. The higher boiling material was then transferred to a vacuum distillation apparatus and distilled under reduced pressure. A summary of the distillation results is presented in the following table:

Head Kettle Refrac- Fraction Temper- Pressure, tive Wt. Wt.

ature, mm. Index at Grams Percent No. 1, Light Materials. 93 1 97. s 29. 2 No. 2, N,N,N ,N

tetraallylpropenel,3-diamine 93-105 1.5 1.4053 57.2 17.1 N o. 3, Unidentified heavier materials 135-200 3 1.5182 27.9 8.3 Residue 200 152.0 45.4

Total 334.9 100 Example IV N,N,N',N'-tetraallylpropene-1,3-diamine and the other materials recovered from the fractionation of Example I were tested for spontaneous ignition employing fuming nitric acid as the oxidant. The temperature of the fuel and oxidant was maintained at room temperature (21 C.). In each test 0.13 ml. of the fuel or a diluted solution thereof was dropped into a 1" x 8" test tube containing 0.3 ml. of fuming nitric acid. The inert diluent (n-heptane) was employed to determine the amount of dilution which each fuel would tolerate and retain'its hypergolic properties. The results are set forth in the following table.

Maximum percent Dilution Fuel Oxidant with n-heptane with Retentlon of Hypergoliclty Fraction No. 1; g ii f k Z3 Fraction No. 2 (N,N,N,N' -tetraallyl 70 propene-1,3-diamlne). 70 Fraction No. 3 Z8 In addition to the room temperature tests previously described, N,N,N',N-tetraallyl-1,S-diaminopropene and other materials recovered from the fractionation procedure of Example I were also tested for spontaneous ignition at -40 C. Prior to testing, the temperature of the fuel and oxidant was lowered to -40 C. Tests were conducted employing 0.13 ml. of fuel or a diluted solution thereof and 0.3 m1. of fuming nitric acid. Results are recorded below.

Maximum Percent Dilution with n-heptane Fuel Oxidant with Retention of Hypergolicity at 40 0.

Fraction No. 2 (N,N,N,N-tetraallyl- {RFNA 30 propene-1,3-ldamine). WFNA 20 Fraction No. 3 {%%fk In addition to the above tests, the crude reaction mixture obtained from the procedure of Example I was also tested for self-ignition properties. Prior to testing, ether and other low boiling materials were removed by heating the reaction mixture in a warm water bath under reduced pressure provided by a water aspirator. Results are recorded below.

Example V A run for the preparation of N,N,N',N'-tetraallylpropene-l,3-diamine was conducted in the manner described in Example I except that the reaction mixture was stirred for 12.5 hours. The reaction mixture was very dark in color and viscous. This material was distilled to remove unreacted diallylamine and other volatile materials leaving a black, plastic residue in the kettle. This material was tested for spontaneous ignition employing fuming nitric acid as oxidant. Tests were con ducted with the fuel and oxidant maintained at room temperature (21 C.). In the first test, a small particle of the solid, plastic residue was dropped into 0.3 ml. of fuming nitric acid in a 1" x 8" test tube. In addition this residue was dissolved in n-heptane and the maximum dilution that the material would tolerate and maintain its self-ignition properties was determined. 0.13 ml. of fuel solution was employed with 0.3 ml. of fuming nitric .acid .as described :in

*7 I I e ,testuprocedure .of .Example -Resu1ts are s'et forth below.

Maximum Percent Dilution Fuel Oxidant with n-heptane with Retention of Hypergolicity Plastic residue X ggf K Plastic residue dissolved in n-heptan e a 316i:

Example VI A run for the preparation of N-,N,N', tetraallylpropene-1,3-diamine was conducted in the manner described in Example 'I}except that the reaction"'mixture was stirred for 16 hours. After filteringioif the potassium carbonate, the reaction mixture was stripped of ether. Then half of the de-e'therified material was refractionated to removeleverything up to diallylaminejunder reduced pressure (hea'd temperature35 C., corn). The remaining half of thi material was refractionate'dto remove everything up to and including diallylamine under reduced pressure (head temperature, 117 C., corn). "These two materials were tested for self-ignition properties at 21 nitric acid wasinjected into the fuel. A constant pressure nitrogen surge chamberprovideda source of 3pproximately 40 p.s.i.g. pressure to inject the oxidizer into the fuel. A solenoidcoil actuated the injector to provide N,N,N,N-tetramethylpropene l,B-diamine Was prepared frorn dirnethylarnine and acrolein bysubstantially the same procedure as previously employed for N;N,'N ',N'. tetraallylpropen'e-l,3-diarnine. The crude materiahinjlli percent yield, was distilled in an 18-inch column. "A percent theoretical yield of distilled product was obtained, along with 22 percent solid kettle residue.

These materials were examined for dilution data and ignition delay with the drop tester using standard technrques.

Toluene Dilution I nition Dela Material B.P., 0. ne Room temp. C. milliseconds RFNA WFNA RFNA WFNA I N,N,N',N Tetramethylpro- 4s. 1. 4589 70 70 10 1o 15.5@ 24C.

. vpens-1,B-diamiue. Crude N,N,N,N'-Tetrameth- 1. 4668 70 70 20 20 10. 5 24 C.

y1pr0pene-1,3-diamine. Plastic kettle product Hypergolic At 10.3 mm. Hg. C. and at 40 C in the manner set forth in'previous examples. 'Results are recorded below: E l 1X Test lfgfgtffifigf Each of the fuel mixtures described hereinbelow was Fuel xi i pta tested for spontaneous ignition employing fuming nitric perature, with Retention V o C Hyper. acid as the oxidant. The temperature of the .fuel and $011? oxidant was maintained at 21 C. In each test, 0.13 RFNA' ml. of the fuel or a diluted solution thereof was dropped Crude product (etherremoved)- 21 g into a 1 inch by 8 inch test tube containing 0.3 ml.'of Do %g fuming nitric acid. The inert diluent was employed to Crude product (ether and dia} 21 8 determlne the amount of dilutlon which each fuel would lylamine removed). 40 tolerate and retain its hypergohc properties. The results WFNA 10 are set forth below.

Maximum Percent Dilution Fuel Composition Oxidant with n-Heptane with Retention of Hypergolicity .-1oo% tert-hutylMercaptan {pggg gs ggtgg ggg E???- 10 volume percent N,N,N,N-tetra- 'Red Fuming Nitric Acid" 20. zallylpropene-Lli-diamine in tert- White Fuming Nitric Acid 10.

butyl mercaptan.

Example VII A drop test apparatus comprising an injection nozzle inserted tO'WiIZhiII 1" of the botto m of a 1 -x' 8" test tube was employed to determine the ignition d'elay in milliseconds of 'N,N,N,N-tetraallylpropene-lg3-diamine. Aismall quantity of fuel (0.2 ml.)':was placed in'the bottom of the" test tube and 0.3 'ml. of whitefuming remove unreacted diallylamine and other volatilema Example X A run for the preparation of N,N,N',N'-tetraallylpropens-1,3-diamine was conducted in the manner described in Example III except that the 'reaction'mixture was stirred for 12.5 hours. The reaction mixture was very dark in color and viscous. This material was dis'tilledqto Example XIII Several additional alkane polyamines and alkenylene polyamines were tested for ignition delays with a drop tester, injecting white or red fuming nitric acid into a small quantity of fuel and determining the ignition delay interval between the contact of the acid and fuel and the Fuel Composition Oxidant Maximum Percent. Dilution with n-Heptane with Retention of Hypergolicity 100 percent tert-butyl mercaptan 5 weight percent of theresidue described above, dissolved in tert-butyl mercaptain.

White Fuming N ltric Acid Red Fuming Nitric Acid Red Fuming Nitric Acid {White Fuming Nitric Acid".-.-

N o ignition. Do.

presence of flame as sensed by a photocell. The ma- Example XI terials and ignition delays are set forth below. A run for the preparation of N,N,N,N-tetraallylpropone-1,3-diamine was conducted in the manner described fil figgg gg g in Example III except that the reaction mixture was 75 F. stirred for 16 hours. After filtering oif the potassium Material carbonate the reaction mixture was stripped of ether. FRed FWhiite A portion of this material was refractionated to remove liiiiz r i l i ii ric everything up to and including diallylamine under re- Acid Add duced pressure (head temperature, 117 C., corr.). This N N N, N T h etramethylet ane-l,2-diarnine 9.3 12 material was admixed with tert butyl mercaptan 1n vary N'NNZI\I, ,I\et,amethylbutam1,Miamme 14 16 mg proportions and the fuel compositions so formed g g b $fgg t g i uteue-3 4 damipen 4. 2 were tested for self-ignition properties by the process de- N; ;N 3 1i .323% g igigifiii ggiiffj1;; N N N N-Ietrameth i-2-buten -1 idiamine. 4. 3 4.3

C t 1 1 1 y e scribed in previous exampl s Results are set forth N,N,N,lN, Tetramethylhexanmywmmme 8.8 as below.

Maximum Percent Dilution Fuel Compositions Oxidant with n-heptane with Retention of Hypergolicity Red Fuming Nitric Acid N o i ition. Percent g g f fi gf s {White Fuming Nitric Acid 1%, 10 percent 0111 6 i A I 6 Red Filming Nitric Acid 20 1,3-diaminopropane (ether and diauylamme removed) White Fummg Nitric Acid 20.

Example XII Several of the alkane polyamines and alkenylene polyamines were tested for ignition delays with a drop tester, injecting white fuming nitric acid into a small quantity of fuel and determining the ignition delay interval between the contact of the acid and fuel and the presence of flame as sensed by a photocell. The materials and ignition de- As will be evident to those skilled in the art, various modifications, substitutions and changes may be made or followed in the light of the foregoing disclosure Without departing from the spirit or scope of this invention.

I claim:

1. In the method for developing thrust by the combustion of bi-propellant components in a combustion chamber of a reaction motor, the steps comprising separately and simultaneously injecting a stream of an oxidant component and a stream of a fuel component into a combustion chamber of said motor, in such proportion as to produce spontaneous ignition, said fuel component consisting essentially of from to 10 percent by volume of at least one mercaptan having the formula RSH wherein R is selected from the group consisting of alkyl and alkenyl radicals having not more than 10 carbon atoms, and from 10 to 90 percent by volume of at least one hydrocarbon polyamine containing at least two groups attached to one or more carbon atoms, wherein each R is selected from the group consisting of a hydrogen carbon polyamine is N,N,N,N'-tetramethylbutane-1-,4-

diamine.

3. A method according to claim 1 wherein said hydrocarbon polyamine is N,N,N,N-tetramethylpropane-1,2 diamine.

4. A method according to claim 1 wherein said hydrocarbon polyamine is N,N,N,N-tetramethylpropane-1,3 diamine.

5. A method according to claim 1 wherein said hydrocarbon polyamine is N,N,N'N'-tetramethylethane-1,2- diamine.

onernercaptan having the formula R'SH whereinR'. is selectedfrom the group consisting of alkyl and alkenyl radicals having not more than 10 carbon atoms, and from 90 tolO percent of at least one hydrocarbon polyaminecontaining at least two i RN- groups attached to one or more carbon atoms, wherein each R' 1s selected from the group consisting of a hydrogen atom and alkyl, alkenyl, cycloalkyl, cycloalkenyl, aryl, alkaryl and aralkyl hydrocarbon radicals, the hydro- .carbon of said polyamine being selected from the same group of hydrocarbon radicals, and the total number of carbon atoms in said polyamine being not greaterthan 30, and up to 70 percent by volume of a normally liquid 6. A method according to claim 1 wherein said hydrocarbon polyamine is N,N,N',N-tetramethylpropene-1,3- diamine.

7. In the method for developing thrust by the combus tion of bi-propellant components in a combustion chamber of a reactionmotor, the steps 'comprising'separately and simultaneously injecting a stream of an oxidant component and a stream of a fuel component into a combustion chamber of said motor, in such proportion as to produce spontaneous ignition, said fuel component consisting essentially of at least percent by volume of a mixture consisting essentially of from 10 to 90 percent of at least one mercaptan having the formula R'SH where in R is selected from the group consisting of alkyl and alkenyl radicals having not more than 10 carbon atoms, and from 90 to 10 percent of at least one hydrocarbon polyamine containing at least two i RN groups attached to one or more carbon atoms, wherein each R is selected from the group consisting of a hydrogen atom and alkyl, alkenyl, cycloalkyl, cycloalkenyl, aryl, alkaryl and aralkyl hydrocarbon radicals, the hydrocarbon of said polyamine being selected from 'the same group of hydrocarbon radicals, the total number of carbon atoms in said polyamine being not greater than 30; and up to 70 percent by volume of a normally liquid l1ydrocarbon.

8. A method according to claim 7 wherein said mercaptan is tert-butyl mercaptan.

captan is allyl mercaptan.

10. A method according to claim 7 wherein said rn'ercaptan is tert-hexyl mercaptan.

11. A method according to claim 7 wherein said mercaptan is isopropyl mercaptan.

12. A method according to'claim 7 wherein said mercaptan is tert-octyl mercaptan. v

I 13. A method according to claim 7 wherein said hydrocarbon polyamine is N,N,N',N-tetramethylbutane-1,4- diamine.

14. A method according to claim 7 wherein said hydrocarbon polyamine is N,N,N,N'-tetramethylpropane-1,2- diarnine.

15. A method according to claim 7 wherein said hydrocarbon polyamine is N,N,N,N'-tetrarnethylpropane-1,3-

diamine. 16. A method according to claim 7 wherein said hydrocarbon polyamine is N,N,N,N'-tetramethylethane-1,2- diamine. r 17. A method according to claim 7 wherein said hydrocarbon polyamine is N,N,N',N-tetrarnethylpropene-1,3- diamine.

18. A fuel composition capable of spontaneous ignition when contacted with an oxidizer, said fuel consisting esse'ntially of .at least 30 percent by volume of a mixture consisting essentially of from-10m '90 percent of at least hydrocarbon. 19. A fuel composition according to claim 18 wherein said polyamine is N,N,N,N-tetramethylbutane-1,4 diamlne.

20. A fuel composition according to claim 18 wherein said polyamine is N,N,N',N'-tetramethylpropane-1,2-diamine.

21. A fuel composition according to claim 18 wherein said polyamine is N,N,N,N-tetramethylpropane-1,3-diamine.

22. A fuel composition according to claim 18 wherein said polyamine is N,N,N',N'-tetramethylethane-1,2-diamine.

23. A fuel composition according to claim 18 wherein said polyamine is N,N,N',N'-tetramethylpropene-1,3-diamine.

24. A fuel composition according to claim 18 wherein said mercaptan is tert-butyl mercaptan.

25. A fuel composition according to claim 18 wherein said mercaptan is allyl mercaptan. v

26. A fuel composition according to claim 18 wherein said mercaptan is tert-hexyl mercaptan.

27. A fuel composition according to claim 18 wherein said mercaptan is isopropyl mercaptan.

28. A fuel composition according to claim 18 wherein said mercaptan is tert-octyl mercaptan.

29. A fuel composition capable of spontaneous ignition when contacted with an oxidizer, said fuel consisting essentially of from 90 to 10 percent of at least one mercaptan having the formula R'SH wherein R is selected from 1 the group consisting of alkyl and alkenyl radicals having not more than 10 carbon atoms, and from 10 to 90 percent of at least one hydrocarbon polyamine containing at least two 7 I groups attached to one or more carbon atoms, wherein each R is selected from the group consisting of a hydrogen atom and alkyl, alkenyl, cycloalkyl, cycloalkenyl, aryl, alkaryl and aralkyl hydrocarbon radicals, the hydrocarbon of said polyamine being selected from the same group of hydrocarbon radicals and the total number of carbon atoms in said polyamine being not greater than 30.

30. A fuel according to claim 29 wherein said hydrocarbon polyamine is N,N,N',N-tetramethylbutane-1,4-diamine.

31. A fuel according to claim 29 wherein said hydrocarbon polyamine is N,N,N',N'-tetramethylpropane-1,2- diamine.

- 32. A fuel according to claim 29 wherein said hydrocarbon polyamine is N,N,N',N'-tetramethylpropane-1,3- diamine. V

i 33. A fuel according to claim 29 wherein -saidhydr'o carbon polyamine is N,N,N',N'rtetramethylethane1,2@diamine. v d

34. A fuel according to claim 29 wherein said hydrO n e i i 2,919,541 13 carbon polyamine is N,N,N,N'-tetramethylpropene-1,3- diamine.

35. A fuel according to claim 29 wherein said mercap- 38. A fuel according to claim 29 wherein said mercaptan is isopropyl mercaptan.

39. A fuel according to claim 29 wherein said mercaptan is tert-octyl mercaptan.

References Cited in the file of this patent UNITED STATES PATENTS Pevere Nov. 12, 1935 Chenicek Dec. 22, 1942 Biswell et al June 20, 1950 Viles June 12, 1951 Malina et a1 Oct. 30, 1951 OTHER REFERENCES Zucrow: Journal of the American Rocket Society, N0. 72, December 1947, page 32. 

1. IN THE METHOD FOR DEVELOPING THRUST BY THE COMBUSTION OF BI-PROPELLANT COMPONENTS IN A COMBUSTION CHAMBER OF A REACTION MOTOR, THE STEPS COMPRISING SEPARATELY AND SIMULTANEOUSLY INJECTING A STREAM OF AN OXIDANT COMPONENT AND A STREAM OF A FUEL COMPONENT INTO A COMBUSTION CHAMBER OF SAID MOTOR, IN SUCH PROPORTION AS TO PRODUCE SPONTANEOUS IGNITION, SAID FUEL COMPONENT CONSISTING ESSENTIALLY OF FROM 90 TO 10 PERCENT BY VOLUME OF AT LEAST ONE MERCAPTAN HAVING THE FORMULA R''SH WHEREIN R'' IS SELECTED FROM THE GROUP CONSISTING OF ALKYL AND ALKENYL RADICALS HAVING NOT MORE THAN 10 CARBON ATOMS, AND FROM 10 TO 90 PERCENT BY VOLUME OF AT LEAST ONE HYDROCARBON POLYAMINE CONTAINING AT LEAST TWO 